Propeller appendage



Sept 8, 1925. ,552,533

. V- N. W. AKIMOFF PROPELLER APPENDAGE Filed Jan. l5. 1924 4K/ff Patented Sept. 8, 1925.

UNITED STATES PATENT QFFICE? NICHOLAS W. AKH/torri, or PHILADEnPnIA, PENNSYLVANIA,

. i i PRQPELLER APPENDAGE.

Application eled January 15, 1924. Serial No. 686,410.

propellers and apparatus associated there-- with, whereby the circulation about the propeller may be positively increased or varied Aas desired.

In accordance with the principles of modern hydrodynamics, the action of a theoretically perfect propellei1 is controlled by a central vortex aft of the propeller, and resulting from they combined advance and rotation of the propeller, which is fed either positively or negatively by fractional vortices corresponding to each blade. rl"lhus the greater the activity of the central core v nor-y tex the greater the circulation about each blade, as the circulation about the blades is intimately linked with that of the central vortex. Obviously, advantages arise from this increased circulation such as greater thrust of the propeller and less danger of cavitation thereof in operation and, so too, this increase in circulation, properly controlled, affords means to regulate the pro-- peller `action and speed thereof within certain limits due to loading,characteristics I,and the like. Y

Propeller appendages have been heretofore in use which rotate with the propeller and increase the circulation .of the central vortex by the action of the friction vor viscosity of the water or air thereon. Other types of appendages have been devised which, driven independently of the propeller and at varying and differentspeeds therefor, strengthen and control the central vortex associated with the propeller and result in y.a corresponding increase and control of the circulation about the propeller.

In the presen-t invention, I aim to provide im appendage for propellers which increases by a suction action the circulation of the central vortex associated with the propeller and which thereby increases also the circulation about each propeller blade, the sum lof which ci,rculationsA is substantially ap roximate to that of the central vortex. l

r further object is to provide Ian appendage for propellers andvassociated apparatus which, by maintaining a suction or vacuum therewith, operates to regulate the action of the propeller by controlling'the icirculation of the central vortex associated therewith.

A further object is to, provide an appendage of the above type for screw propellers by which the circulation of the central vortex from the propeller may be increased or diminished within certain limits and the cor-- responding speed of the propeller varied within these limits.

A further object is to provide a device of the above mentionedl character in which the central vortex associated with saidy propeller isincreased by suction acting on the vortex associated with said propeller.

A .further object vof my invention is to provide an appendage yand suction. apparatus associated therewith, operatingwith a propeller whereby the circulation of the medium about .said propeller may be varied by vary# ing the suction acting on said appendage.

A further object is to provide anappendage for propellersand apparatus associated therewith attaining the objects stated labove which is simple, reliable iand efficient in operation and which may Vbe installedwitli various types of propellers and at yaininimum cost. y'

Other. objects of the invent-ion ,thanthose stated above, together with the advantages inherent therein, will be. in part obvious and in part specific-ally referred to in the course o-f the following description of the various elements, arrangement of parts, coinbinations thereof, and application of princig ples constituting the invention; and l"the scope of protection contemplated will appear from the claims. f

In the accompanying drawings, which are to be taken as part of thel vspeciication Y and in'which I have shown the preferred form or embodiment of my invention- Figure l is an elevation, `partly insection, Vof the appendage and associated rdevice applied to a boat or ship; and i Figure 2 is an enlarged section of certain parts as shown in Figure l.

' Referring now to the drawings and more particularly to Figure 1, 10 designates the rear end of the hull of a boat adapt-ed t0 bedriven by a propeller 11 lof the usual design mounted on a drive shaft 12 Ldriven by any motive means (not shown) .A Meunted 0.11 the hub @if .the propeller 11 by any vsuitable means, such vas by bolts, and rearl wardly thereof, is an appendage 13 so positioned as to be located, inV reality, in the core of the vortex associated with the propeller while in-motion.- rIhe appendage 13 is cast hollow, but is closed at Mitsaft end and is provided with a plurality of longitudinal slo'fts 14, say,v twelve in num-ber. These slots 14 thus render the hollow appendage 13 open to the surrounding medium, such as water, as in the present case;

The drive shaft'12 is hollow fora portion of its length from its rear end frontwardly and has its aft end open to the hollow appendage 13, so thatthe surround-V Vstufiingxboxes 17 and packing 18 whereby ing water may flow through the slots 14:'

into the interior of the appendage 13 and through the lholllow drive *shaft* 12;

llositioned'inside of the boat in any convenient location, and surrounding the .drive shaft, is a suction chamber lprovided with a vacuum set up therein can be maintained air and water tight. A series ofo-penings 20 are provided in the portion of the shaft 12surroundedby the chambery 16, serving as passageways from the hollow bore lthereof to the suction Vchamberl. A vacuumis maintained in the chamber 16 `by anyY desirable meansfas bya vacuum tank 21, whichl is united thereto by theconnecting pipe 22; A .dischargeoutlet is provided inthe` tank y 21 and includes a pipe 23 leadingto a dischargeY nozzle or'valve 24 whereby an excess of water in the suction tank 21 mayA bedischarged overboard,or inboard,`for anypurpose desired. A valve 25 is provided in the pipe line 22 adjacent the suctionbhamber v16 whereby. they amount of vacuum. in the chamber 16 may be readily controlled'. For the purpose of cleansing or blowing vout any dirt or matten-which accumulates Yin thevtank V16, an air compressor 26 is provided adjacent theV chamber 16 and com pressed air maybe led thereto through the pipe line 27.. Y

The operation of the device is, of course, obvious from the above. A vacuum set up the chamber" 16 through the mediumv of .thevacuum tank 21 causesthe lwater surs rounding the appendage andY propeller Y13 and 11- respective-ly to be drawn intov the f appendage through the slots Hand through ,the hollow shaft 12 to the Vchainberl and through the vacuum tank 21 and discharged therefrom. Upon rotation of. the propeller 1 1, a central vortex resulting from its rotation and advance, isset up which, .bythe faction ofthe appendagerotating with Vthe propeller and fthe suction means "hereincorresponding control of the increase or decrease of the circulation set up. A pump or'siphon might also be efhciently used to create a vacuum in the chamber 16, and

such is sought to be coinprehendedy by my invention.

Inasmuch as many changes could be made in the above construction and many appar-` ings shall be interpreted as illustrative andV not in a limiting sense.V It is also to be understood that thelanguage used in the following claims isa-1nytended toncover. all of the generic and spe-v cific features of the invention Yherein described and all statements' of the scope ofthe invention which, as a matter of fact,' ina y be said to fall therebetween. .f

I claim:

. 1. In combination with a propeller and an j appendageetherefor, suction rmeans operative Vto induceY increased circulation fof-the centraly vortex associated with said, propeller.

2. Incombination with apropeller, mea-ns rotatable therewith, operative toincrease the circulation of the central vortex associated with said propeller," said means comprising a whollowfinember rearwardly of saidpropeller, adapted to exertV avacuum'on 'the peller,saicl means `comprising an appendage axially mounted with relation to said propeller, and ineansadapted tof exert suction Yon thewater surroundingsaid appendage.

4. In combination with a propeller, -a drive shaft .upon which saidY propelleris mounted, hollow throughout a portion of its length, an appendage mounted vonsaid drive :shaftrrearwardlyofsaid-propeller and being .open to the surrounding medium; and

Vmeans adapted to exertasuction pressure through said drive :shaft andy appendage up'onthe surroundingmedium.. f

In= combination with a rpropeller, a main shaft hollowu forV a portionofl its.; length, upon which said .propeller-is mounted, Ya hollow appendage .mounted L onjsaid main shaftrearwardly of said propeller, said appendage Y having longitudinal@ `slots therein, and means adapted vto 4exert al vsuction through said drive shaft andV appendage upon the snrroundinginedium whereby to increase the `circulation about'said propeller.

. -6-. In combinationfwith a propeller,.ja main. drivefshafft upon ,which said propeller is mounted, a hollow appendage, mounted on said prcpeller and ,rearwardly'lthereot said appen age having longitudinal slots therein, said drive shaft being hollow for a portion of its length, and means to exert asuction action through Said drive shaft and appendage upon the surrounding medium whereby to increase the circulation aboutsaid propeller, and means operative to vary the suction pressure through said drive shaft and said appendage.

7. In combination with a propeller, a main drive shaft upon which said propeller is mounted, a hollow appendage mounted on said propeller and rearwardly thereof, said appendage having longitudinal slots therein, said drive shaft being hollow for a portion of its length, a chamber surrounding said shaft, passageways leading Jfrom the hollow portion of said shaft to said chamber, means to create a vacuum in said chamber, whereby such vacuum is transmitted to the water surrounding said appendage through said drive shaft, and mea-ns to vary the vacuum set up in said chamber as desired.

8. In combination with a propeller, a

main drive shaft upon which said propeller is mounted, a hollow appendage mounted on said propeller and rearwardly thereof, said appendage having longitudinal slots therein, said drive shaft being hollow for' a portion of its length, a chamber surrounding said shaft, passageways leading from the hollow portion of said shaft to said Chamber, means to create a vacuum in said chamber, whereby such vacuum is transmitted to the water surrounding said appendage through said drive shaft, means to vary the vacuum set up in said chamber as desired, and means to clean said chamber.

9. In combination with a propeller and an appendage therefor, suction means operative through said appendage to induce increased circulation of the central Vortex associated with said propeller.

In witness whereof I have hereunto signed my name.

NICHOLAS W. AKMOFF. 

